Direct Asymmetric α-Sulfamidation of α-Branched Aldehydes: A Novel Approach to Enamine Catalysis
作者:Henning Vogt、Thomas Baumann、Martin Nieger、Stefan Bräse
DOI:10.1002/ejoc.200600587
日期:2006.12
catalyst, aldehyde, sulfonyl chloride and sodium azide. The proposed mechanism differs fundamentally from the mechanistic model usually ascribed to enamine catalysis, containing as a key step the diastereoselective cycloaddition of the azide to an enamine formed in situ. The products obtained in the reaction can be converted into the corresponding unnatural amino acids in two additional steps.(© Wiley-VCH
α-支化醛和磺酰叠氮化物之间的脯氨酸催化反应提供了比例结构稳定的 α-磺酰胺化产物,ee 值高达 86%。反应也可以用催化剂、醛、磺酰氯和叠氮化钠以一锅法进行。所提出的机制从根本上不同于通常归因于烯胺催化的机制模型,其中包含叠氮化物与原位形成的烯胺的非对映选择性环加成反应作为关键步骤。反应中获得的产物可以通过两个额外的步骤转化为相应的非天然氨基酸。 (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)